How to Grow Viscaria Plants

Silene viscaria plants with small pink flowers on thin stems and thin foliage surrounding

The Spruce / Evgeniya Vlasova

An easy-to-grow annual, the viscaria plant is known for its vibrant purple blooms. Viscaria plants are members of the Silene genus and carnation family (Caryophyllaceae). When planted alone, these erect, stiff-stemmed plants can appear almost weed-like, but together, they create a carpet of color. They grow easily from their flower seeds and are easy to maintain. These flowers are an ideal choice if you happen to live in a warmer climate and can plant them in a spot with abundant sunshine between the months of February and May. These fast-growers should bloom within six to eight weeks of sowing seed.

Botanical Name Silene viscaria (also classified as Viscaria vulgaris or Lychnis viscaria)
Common Name Viscaria, sticky catchfly, clammy campion, rose of heaven
Plant Type Perennial
Mature Size 12-18 in. tall
Sun Exposure Full, partial
Soil Type Well-drained, sandy, loamy
Soil pH Slightly acidic to slightly alkaline (6.1-7.8)
Bloom Time Summer
Flower Color Purple
Hardiness Zones 3-8 (USDA)
Native Area Europe (Iceland), North America (Canada, Greenland), Asia (Kazakhstan, Siberia)
Toxicity Non-toxic

Viscaria Plant Care

When planting viscaria, you'll have the best results when sowing them in the ground, although they can be planted in pots and then later transplanted. They should be planted about 6 inches apart. You can expect to see their gorgeous purple blooms in the summer months (June through August).

Viscaria flowers will generally start as small, grass-like tufts of foliage, eventually reaching about 5 inches in height before producing flowering stalks. Viscaria is also called sticky catchfly, clammy campion, and rose of heaven. Its "sticky" nickname comes from its gummy, viscous substance that catches bugs nosing around. The stalks can rise as high as 12 to 18 inches tall. Viscaria plants are usually stiff enough to hold their own weight, but if you plant one of the taller varieties of viscaria, you may need to provide stakes or other forms of support.

Consider viscaria plants as a way to add a colorful border to a rock garden or any other dry areas. The viscaria flower contains brassinosteroids, a substance used in plant strengthening formulas and fertilizers. They can help to promote disease resistance and the overall health of any flowers planted nearby. However, they are susceptible to slugs and snails, which can damage foliage.

Silene viscaria plants with thin stems and small pink flowers on ends

The Spruce / Evgeniya Vlasova

Silene viscaria plant with small pink flowers and buds on thin stems closeup

The Spruce / Evgeniya Vlasova

Silene viscaria plant stem with small pink five-petaled flowers and foliage

The Spruce / Evgeniya Vlasova

Silene viscaria plant stems with small pink flowers closeup

The Spruce / Evgeniya Vlasova

viscaria flowers

The Spruce / Evgeniya Vlasova

Light

The viscaria will thrive in both full sun and partial shade. However, they should ideally receive full sun for at least half of the day. Though they can tolerate partial shade, bright sunlight will help bring out the plant's vibrant colors and promote stem strength.

Water

Viscaria plant is undemanding and somewhat drought-resistant, but don't let your plants become too dry. Water either in the morning or evening, as opposed to the midday, particularly on sunny days. Plus, don't let the soil become waterlogged; it might cause root rot and kill the plant.

Soil

Viscaria can grow when planted in a wide range of soils. However, steer clear of heavy, wet soil. Well-drained soil is best, and they will thrive in slightly sandy, loamy soil.

Temperature and Humidity

These are hardy plants that can tolerate a bit of frost. Some varieties of viscaria can survive freezing temperatures. It's generally best to plant these plants after the coldest part of the winter has passed.

Fertilizer

Viscaria plant doesn't require fertilizer, but it can help promote healthy growth. Liquid fertilizer can be used during the summer. However, for best results, apply monthly throughout the warmer months.

Viscaria Varieties

Several subspecies often get confused for varieties or cultivars for Silene viscaria. The most common cultivar, 'Splendens Plena,' features bright pinkish magenta double flowers. It is also sometimes sold as 'Splendens Flore Pleno' or 'Flore Pleno'.

Pruning

Viscaria plants don't require extensive pruning; however, you can deadhead spent flowers to encourage fuller blooms. Trim inflorescences or flowering stalks to about two inches, and prune stems and branches after the flowers have bloomed. Time your pruning to before the seeds have matured, so the plant puts its energy toward its flowers instead of forming seeds.

Propagating Viscaria

Viscaria plants can be propagated in a few different ways: seed, offsets, or division. Viscaria plants that are rooted outdoors should freely self-seed. The best time to start sowing seeds is between February and May. They will take about two weeks to germinate (in temperatures between 64 and 68 degrees Fahrenheit). Once the plant begins to produce its grass-like tufts, you can transplant them to garden beds or plant containers.

Potting and Repotting Viscaria

When planting viscaria in containers, it's important to sow only a few seeds per pot (and thin the seedlings to just one plant per pot). Transplant potted plants every couple of years to fully replace the soil and provide a larger pot for the root system.

Overwintering

Viscaria is native to the cold tundra of Siberia and is hardy down to -25 degrees Fahrenheit. If you are planning to overwinter viscaria outdoors in containers in extreme frigid temps, those plants will need winter protection, such as placing them on wooden blocks and wrapping them in fleece.